A few weeks ago, family members crowded around 5-year-old David Briscoe's bed in the pediatric hematology/oncology unit at Inova Fairfax Hospital. But David -- whose sleeveless Superman T-shirt hid medical tubes running down his chest -- was more absorbed with another visitor: a Chihuahua named Olive, who was nosing curiously around in his sheets.

Together with her owner, Carolyn Caruso of Alexandria, Olive visits the hospital's pediatric floors twice a month through the nonprofit pet-therapy group People Animals Love (PAL).

PAL visits -- by calm, people-friendly dogs of any size -- take place with patients of all ages in hospitals, nursing homes and psychiatric facilities throughout the area, said the group's founder, Earl Strimple. All volunteers and dogs take a three-hour training course. The group accepts only dogs for visits to health care facilities; male dogs must be neutered to participate. Other PAL programs, such as a summer camp for at-risk kids, welcome various types of animals.

In her 21/2 years at Inova Fairfax, Olive has become known as "The Singing Chihuahua." When her owner sings "Happy Birthday," Olive joins in.

When Caruso and Olive performed for Briscoe -- howling and singing in unison -- the young patient smiled. A family member broke into tears. Parents and family are often moved by the visits and the reactions they prompt in sick children, said Caruso.

For PAL's next volunteer orientation and training sessions, which take place in Northwest, call 202-966-2171 or see www.peopleanimalslove.com.

-- Samantha Sordyl

Olive the Chihuahua gets a hug from David Briscoe, 5.